The BlackBerry calendar doesn't support multiple calendars in the way that the computer side, in your case iCal supports them. The BlackBerry can do multiple email calendars, but there isn't any way to sync those separately with any of the current sync tools out there.
Also, I am unaware of a third party BlackBerry calendar application that supports this either.
https://support.markspace.com/index....169&nav=0,3,75